Piston cooling



Feb. 13,1945. -E.WAEBER 2,369,500

PISTON COOLING Filed Dec. 22, 1941 'int0thep18m Patented Feb. 13,

encased} "IIPISTQQODOHNG mih'waehei Switzerland, t shher new sw fmlmqrmllwuv 53' museum December. 1041; No. teases I In SwitserlandFebruuyLlDtl W i eclaimar icl. its-+1") 1 This inventlonirelates to an improved pist n for an internal combustion engine, of which is rotatable in the engine. cyil'nder improved rotatable piston of the invention coins prises means for passing cooling oilthrqugh the connecting rod, thenthrflughia ww 'm'the'pik T ton into contact with a cooling suriac'e er the piston, with duct means for returning the oil irojm the said space to the crank case 'oi'the engine, and at least one oil scraper ring on the piston. The oil which is forced throulh the connecting rod into contact with the inner surface of the.

piston is. permitted to fiow ireely back into the crank case of the engine.

Liquid-cooled pistons give rise to difliculties in Fig. 2- is a section view along the line 2-1 'of Fig. 1.;

The piston i has within v core member 2, which. forms at one side with the member/i0. the closing member l'which is prosemi-spherical bearing surface I,

"msrod deliveringoil to a quickly moving piston from a 4 stationary place-through hydraulically-ti ht dea vices and in returning the oil to the stationary place through other hydraulically-tight devices. If a suitable oil is used for the cooling. losses,

through leakage at the hydraulically-tight devices may be permitted. But if, as in the invention, one of the hydraulically-tight devices is altogether omitted in order to simplify the piston, and the oil heated on the piston cooling-surfaces is ejected direct'into the crank case, it is possible that the loss of oil may become impermissibly great. The piston, heavily sprayed with oil, will allow-particularly after a long period of; working-the oil to pass into the combustion space.

where it isburut and therefore lost for lubricating purposes. It, as proposed by the invention, the piston is fitted with a device which superimposes a rotary motion onthe reciprocating .motion of the piston, thepiston in the course of service will become always more gastight in the cylinder in consequence of the grinding action orthese combined movements. Grooving can no longer take place, so that an absolutely reliable oil-cooling, with the oil for-simplicity ejected direct into the crank case, is ensured without any impermissible losses of oil.

it is preferable to adopt the. lubricating oil or the connecting-rod iointin the piston as coolingoil. This cooling-oil cansuitably be introduced through the connecting rod. Further simplifiestion of the piston is obtained if the cooling-01h is eiectedin a free iet from connecting rod The accompanying proved piston for an embodyin the invention, in which:

Fig. iisasectio nalsideviewofthepistomand illustrates an iminternal combustion 7 and is thendeiected througha number of-further bores ll into the crank case under the piston of,

. piston crown thezboundary of the cooling-space, 3 within the piston, and has at the other side a surface 4 for the ballem -sp ic hea i o th M ri e connecting rod I. The annular Vii-1 w th a mmedhte piece which acts as a connectin} druini'the eore'm'ember I and the piston body i iheld togetherby-a number 01 bolts ll.

clearance between the ball head I, the connect- I. and the ball cups 4 of the core member 2 and theclosina member s. shims I: are pro- .vided between the core member 2 and the connecting drum I, v.

. Through the as is lubricating oil is intro- I duced to the bearing surfaces 4 and .l. The bore It connects-to a bore It in the core member'l,

.an'd through-this latter a part of the lubricating oil passesas cooling-oil into the cooling-space 3. After passing over the cooling-surface iiof the. piston body I the heated. cooling-oil flows through a'number-of bores it into the annular space H the internal combustion engine. The ball-head 6 has fitted thereover, in an annular groove, two spring rings 2! and it which are each slit at It and 24 respectively. Theexterior grooved surfaces of the spring rings are normally in pressing engagement with the inner cylindrical surface of the. annular intermediate member 0. The lugs II and 20 of the ball-head fit rather loosely in slots" and ti respectively. When the piston reciprocates, the connecting rod I swings in the direction of the arrows with point 2|. as a center of rotation. The lugs l8 and 20 each oscillate in the slots ill and ii as shown by the arcs '22.

when the connecting rod swings toward the left, the 1118"" swims toward the right and this forces the split ring 25 towards the right, closing the slit II, thereby decreasing the diameter of ring 2|, releasing it from engagement with mem- At the same time, the lug I! swings toward the left and expands the ring 26, thus, in:

, creasing its frictional engagement withthe'mem- Y her thereby causing the piston-to rotate in aclockwise direction as'viewed from above; when the connecting rod I swings toward the right.-

its head and skirts,"

In b hble tdlfi aintain the proper running the. lug 20 swings toward the left expanding the ring 25 into gripping engagement with the memher 9 and the lug l9 swings toward the right, de-

motion the oil scraper rings 21 and the cylinder surface will become polished in the course of service, and the formation of grooves will be prevented. Both at the oil scraping rings and at the cylinder, hard highly-polished sliding surfaces will be formed, which will prevent oil flowing through from the crank case into the combustion space.

Only by' obtaining hydraulic tightness with the help of the grinding motion of the piston, will it be possible without excessive losses to maintain reliably a simple form of oil-cooling with ejection of the cooling-oil.

I claim:

1. A rotatable piston comprising an integral head and skirt for a ball-head connecting rod which comprises bearing means inside the piston for engaging the ball-head, a pair of spring rings inside the piston, means for expanding and contracting each ring alternately by the swinging action of the connecting rod to rotate the piston in small increments in one direction, one ring 'about its axis due to the swinging motion of the piston connecting rod, means for passing a cooling oil into contact with a cooling surface on the inside of the piston, duct means in the piston for flowing the oil away from the cooling surface and out of the piston, and at least one oil scraper ring for the piston in the lower portion of the piston skirt.

' v ERWIN WAEBER. 

